The mission of the UCSF-GIVI CFAR Virology Core is to provide innovative and high quality virology to enhance the multidisciplinary research mission of the Center. To fulfill its goals, the Virology Core actively engages CFAR investigators, other core laboratories, NIH-sponsored clinical trial networks and industry partners by: 1) delivering a broad range of laboratory services and molecular diagnostics to support studies of HIV-infected subjects; 2) developing and implementing cutting edge technologies to allow investigators to extend and explore new experimental areas; 3) facilitating technology transfer through collaborations with industry and laboratories including those in resource-limited settings; 4) providing support for high priority CFAR initiatives including projects focused on viral latency and viral eradication, pre-exposure chemoprophylaxis and vaccine trials for prevention of HIV transmission, HIV infection in women and in aging subjects and the causes and consequences of antiviral drug resistance; 5) taking the lead on creating synergy between CFAR cores to provide improved service and enhanced efficiency; and 6) mentoring and training of staff, trainees and scientists, especially those inexperienced in virology, with the aim of enhancing their research programs and career development. The Virology Core has a proven track record. During the last 4 years, this Core played a key role in 129 research studies and clinical trials supporting $33 million in NIH-sponsored projects at UCSF and affiliated organizations, contributing data to 66 manuscripts and presenting its findings at high-profile international research conferences. The Core has also provided laboratory support for 45 independent investigators of which nearly half are at an early career stage. The Core leadership has also actively mentored and trained 27 students and fellows, many of whom now lead active research programs. Further, the Core has provided clinical drug resistance genotyping to hundreds of healthcare providers under CLIA conditions, and actively consulted with providers in interpreting these test results. Finally, the core has provided 24 new assays and services, many of which represent state-of-the-art diagnostics to measure complex viral populations that fills a key unmet research need. Going forward, the Virology Core will continue to tailor its portfolio of services to meet the new challenges emerging in HIV research that are identified as a part of the UCSF-GIVI CFAR strategic planning process. Increased emphasis on international work will also occur.